The ACT is a curriculum-based test testing students in English, Mathematics, Reading and Science Reasoning. Since the ACT has a Science Reasoning section and its Math section measures at a higher level (trigonometry) than the SAT Reasoning Test (geometry), students strong in these fields may benefit by taking the ACT. Additionally, some students applying to the most competitive universities will prefer the option to complete their admissions test requirement in one testing date (ACT with Writing), rather than two (SAT Reasoning Test on one testing date, SAT Subject Tests on a second date).

For more information please view, http://www.fulbright.org.uk/study-in-the-usa/undergraduate-study/admissions-tests/act